Electroplating apparatus



Aug. 18, 1931f J. w. HUGHES 1,319,603

ELECTROPLATING APPARATUS Filed Sept. 2l, 1928 2 Sheets-She 2 INVEN TOR.

. JAMES W. HUGHES. BY

A TTORNEY.

Patented Aug. 18, 1931 UNITED STATES PATiszNT OFFICE JAMES W. HUGHES, OFPHILADELPHIA, PENNSYLVANIA, ASSIGNOR T BUDD WHEEL COMPANY,PHILADELPHIA., PENNSYLVANIA, A CORPORATION 0F PENNSYL- VAN IAELECTROPLATIN G APPARATUS Application -led September 21, 1928. SerialNo. 307,397.

plating operations are carried on continu# ously and automatically.

Among the primary objects of this invention is the provision of anapparatus which is capable of automatically and sequentially subjectingthe articles to be plated to a series of successive treatments wherebyto secure a more uniformly plated product than is now obtainable.

A further object of the invention is the provision of an apparatus forelectroplating cap nuts and other small articles, the apparatus beingoperable to automatically and continuously advance the articles throughthe several baths which are generally employed in the plating process.

A further and important object of the invention is the provision ofmeans for automatically changing the point of contact between thearticle to be plated and the cathode terminal of the electrolyte bathduring the passage of the article through the bath,

thereby eiecually precluding the possibility of certain portions of thearticle receiving less coating than the remaining portions. One of thegreatest difliculties encountered prior to this invention has been toattain an absolute uniformity of coating over the entire externalsurfaceof the Work, this difficulty being due principally to the fac'. that noadequate provision was ever Iliade for constantly shifting the Work asit advanced through the electroplating bath such that no single pointthereof remained in contac'; with the cathode terminal.

A further object ofthe invention is the provision of a continuous lineof different treating baths in combination Withmeans for automaticallycausing the articles to be plated to be progressively advanced incontinuous succession through these baths, this means being operative tosuccessively feed the articles into 011e end of one bath for subsequentydischarge from the opposite end thereof into the adjacent end of thenext bath and so on in continuous sequence and without intermediatemanual handling.

A further object of the invention is the provision of an apparatusemploying for each bath a continuous conveyor equipped with a series ofWork propelling elements, which in certain instances may form thecathode terminals of the electrolyic' bath, these elements being soarranged that they are each operable to propel one or more of thearticles to be plated through that particular bath with which saidelements are associated, each of the baths being in turn provided with aWork guiding trough 'the bottom of Which is of irregular formation suchthat as the articles are propelled therethrough they are tumbled aboutto expose every portion of their external surfaces to the action of thebath. l

A further object of the invention is the provision of means forpreventing excessive deposition of metal on the work propelling elementsWithout interruption of the current and without affecting the constantshifting of the Work with respect to the cathode terminals, the resultbeing that While very little, if any, metal is electro- -5 depositedupon the propelling elements no part of the external surface of theconstantly shifting work is shielded from the metallic deposit.

A still further objectof theinvention is the provision of an apparatuscapable of securing an' increased output of plated articles in a given-time with the expenditure ofk minimum effort, the articles treated bythis apparatus being each provided with a plated coating of uniformthickness in every portion of' its external surface.

Other. objects and advantages of the invention will be apparent morefully hereinafter.

With the above objects in mind, the invention consists substantially inthe combination, construction, arrangement and relative arrangement ofparts, all as will be described more fully hereinafter, as shown in theaccompanying drawings and as finally pointed out in the appended claims.lVhile the particular forms of the invention, as described hereinafterand as shown in the accompanying drawings, are designed to plate 100 capnuts for automobile wheels and the like, it is to be clearly understoodthat the invention is in no sense limited to use with or for the platingof any particular article or device, it being obvious that variousfeatures thereof are applicable for general use'in.-

electroplating machines irrespective of the character, shape or form ofthe articles to be treated. It is to be furthermore understood that theaccompanying drawingsillustrate what is regarded at present as thepreferred forms and embodiments of the invention and that the inventionmay be changed in many respects without'departin essentially from thespirit or scope thereo as defined in the appended claims.

In the said accompanying-drawings:

Figure 1 is a longitudinal section through a portion of the apparatusconstructedin accordance with this invention;

Figure 2 is a top plan view of the receiving end of the tanks;

Figure 3 is a horizontal sectional view taken on the line 3 3 of Figure1 showing the discharging end of the tank;

Figure 4 is a longitudinal vertical sectional view taken on the line 4 4of Figure 3;

Figure 5 is a transverse vertical sectional view taken on the line 5- 5of Figure 1;

Figure 6 is a transverse vertical sectional view through a modified formof apparatus embodying the features of this invention; and

Fi re 7 is a sectional view taken on the line -7 of Figure 6.

Referring now to the ticularly to Figures 1 to 5 thereof, it will beseen that the apparatus of this invention comprises a series oftreatingtanks arranged end for end to provide a continuous line of tanksthrough' which the articles to be plated may be successively passed. Asmany tanks may be employed as are necessary for treating the work beforeit is finally delivered from. the apparatus. The drawings illustrate anapparatus for electroplating cap nuts but, as explained hereinbefore,the apparatus may be employed with equal effect and efficiency inplating articles other than cap nuts.

tank or tanks wherein the articles to be plated are subjected to a bathcontaining lye or other suitable cleansing fluid for removing anygrease, oil or dirt that may have been on the., articles. From thecleaning tank or tanks the articles are passed into a rinsing tank forridding the articles of all .traces of the cleaning Huid. The articlesthen pass from the rinsing tank into the plating tank wherein thearticles are subjected to a bath of electrolyte suitable for the platingprocess. After leaving the plating tank or tanks the article may againbe passed Ythrough a rinsing tank. If the articles are to be platedsuccessively with different drawings and par- The first of the seriesofy tanks is usually designated as the cleaningv metals so as to provideupon the external surface thereof superimposed layers of metal, such ascopper, nickle and silver, (as is done in high-grade silver plating)'the articles may be passed through suitable rinsing tanks arrangedimmediately in advance of and immediately after'each of the separateplating tanks which may be employed.

In the drawings, only the plating tanks are shown, these tanks beingdesignated generally by the reference numeral v10. Inasmuch as themechanism for progressively advancing the work through the apparatus isthe same for each tank, irrespective of whether the tank is employed forcleansing, rinsing or plating purposes, only one of these mechanisms hasbeen shown in its entirety, the adjacent mechanism-for the nextsucceeding tank being only partially shown. ,These article propellingmechanisms are designated generally by the reference numeral 11. Forconvenience of description that end of each plating tank 10 whichreceives the articlesto be plated is termed the box of considerablygreater length than width or depth. Arranged uponthe bottom of the tankand extending between the end walls 14 thereof is an upwardly presentingchanneled member 15, formed preferably ofporcelain or other suchmaterial, this member constituting a trough 16 along'which the articlesto be plated may -be advanced in the manner to be described more fullyhereinafter. As appears most clearly in Figure 5, this porcelain channell5 is of an overall width and depth respectively less than the effectivewidth and depth of the tanklO, the cross sectional area of the channelybeing such as not to materially reducelthe capacity of the tank 10. Thetanks 10 ,are each'filled4 with a suitable electrolytic solution, lthelevel of which is normally maintained immediately below the upperedges'of the tank. Preferably, the channel'l is arranged centrallybetween the side walls 13 of the tank. It will be observed that the endsof the channel 15 are curved upwardlv and toward the opposite -end walls14 of uthe tank such that the botous passage for the lwork throughoutthe entire series of baths. A

Extending longitudinally along and projecting inwardly from theupper'edges of the sidewalls 13 of the tank 10 are a pair of metallicplates 18 secured in position by the screws 19. The free inner edges ofthese plates terminate in vertical planes arranged intermediate theproximate side walls of the channel 15 and the tank 10. Secured to theunder surface of each of the plates 18, preferably by the screws 20, isa second metallic plate 21, the inner edge of which has formed thereon arelatively wide flange 22 providing a shoulder 23. This shoulder 23 andthe inner edge of the plate 18 cooperate to form therebetween arelatively shallow channel or runway 24, -one such runway being providedto either side of the trough 16. If desired, the plates 18 and 21 couldbe made integral and the longitudinally extending runways 24 could beformed in the upper surface thereof, it being understood that in eitherform the runways are spaced apart to provide a centrally arrangedlongitudinally extending opening 25 in the top of the tank through whichaccess is had to the trough 16.

Suitably journalled above the tank adjacent each end thereof are a pairof rotatable shafts 26 upon each of which is secured a pair of sprocketwheels 27 for driving the endless conveyor chains 28. The wheels 27 areso arranged that the lower sections of the chains 28 travel respectivelyin the runways 24 provided in the top of the tank 10, thereby precludingany tendency for the chains to sag at points between the sprocketwheels. For reasons to be explained more fully hereinafter, the lowerchain sections are in continuous electrical engagement with theirrespective runways 24. As appears most clearly in. Figure 1, each chaincomprises a series of interconnected links 29, each of these links beingin turn provided with an inwardly projecting tab or equivalent element30.

. Intel-connecting each pair of opposed tabs 30 is a transverselyextending link or strap 31, each strap being detachably secured inposition by bolts 32 passing through suitable apertures provided in thesuperimposed portions of the tabs and straps. It will thus appear thatthe conveyor adapted to be driv en by the sprocket wheels 27 includes aplurality of uniformly spaced, transversely extending straps, theintermediate portions of which are caused to move successively over thelongitudinally extending opening 25 in the top of the tank 10. Suitablysecured to each of the straps 25 is a cathode element 33 in the form ofa transversely arranged plate` one branch 34 of which is bent over theinner surface of its supporting strap for securement Vthereto by asuitable wing bolt 35. As appears most clearly in Figures -land 5, thesecathode plates, which project outwardly from the conveyor, are each of alength and widthdesigned to permit the j lower ends thereof to passfreelybetween the side walls of the porcelain trough 16. The cathodeplates are each electrically connected to their respective supportingstraps which latter are in turn electrically connected to the conveyorchains 28.

The electrolytic bath is supplied with current frompa suitable source ofsupply (not shown), the negative terminal of which is connected in anypreferred manner to one or both of the metallic plates 18 and 21. Thepositive terminal of this source is suitably connected to the anodeconductors or bus bars 36 which extend along the upper edges of t-heside walls of the porcelain trough 16. N ot only are the plates 33employed as cathode elements, but they are also utilized as the meansfor propelling the work through the trough 16. As appears clearly inFigure 1, the articles to be plated, in this instance the cap nuts a,are received at the receiving end of the tank 10, one or more nuts'being propelled therethrough by each of the continuously advancingcathode plates 33. Inasmuch as these plates are always in contact withthe nuts as the latter are propelled through the trough 16, the currentwhich is derived from-the anodes 36 passes through the electrolyte tothe nuts being plated and finally to the cathode plates 33 and from themto plates 18 and 21 and then to the negative terminal of supply, the

result being that there is continuous deposition of metal upon .the nutsas they are progressively advanced through the electrolytic bath.

As mentioned above it is one of the primary objects of this invention toinsure the uniform plating of every portion of 'the work and inaccordance with this object it will be observed that the bottom of thetrough 16 is given van irregular formation, as at 37. Preferably thisirregular formation is obtained by forming the trough bottom withalternate transverse .ridges andv grooves which operate to constantlytumble the nuts about as they are propelled along the'bottoin of thetrough. There is thus provided an effective meansl for automaticallychanging exception of that portion which contacts With the Work. Thesleeves 38, if desired, may be removable.

Figures 6 and 7 show a modified construction of the apparatus whereinthe propelling members are separate and distinct from the cathodeelements. In this mod `v ified arrangement a longitudinallyextendingporcelain member 40 is employed which differs from the member15 shown in Figures l to 5 in that it is provided with a plurality ofseparate relatively narrow troughs 41 in place of the single wide trough16 hereinbefore described. The propelling members 42, which are securedto the conveyor in substantially the same mannerv as the members 33 ofFigure 1, differ from the members 33 in that the free ends thereof areeach slotted, as at 43, to provide a' plurality of projections 44arranged to' travel respectively through the individual Vtroughs 41. Inan arrangement of this sort only one article may be propelled througheach trough 41 by one of the projections 44. Deposition of metal uponthe propelling members 42 is eifectually precluded by covering thesubmergible portions thereof with suit-- able insulation 45.

Arranged upon the bottom of each of the individual troughs 41 is alongitudinally extending bus bar 46 constituting the cathode elements ofthe electrolytic bath. In order tol insure constant agitation of thearticles to be plated as they are advanced along these cathode barsthrough the troughs 41, the upper surface of each bar is corrugated, asat 47, (see Fig. 7) to provide an irregular formation along the bottomof its respective trough. By reason of the fact that the Work isconstantly in contact with the bus bars 46, which latter are connectedto the negative terminal of a suitable source of supply (not shown),there is a continuous depositmn of metal upon the work. Furthermore,7due to the fact that these cathode bus bars are corrugated the Work, asit is progressively advanced through the troughs 41, is constantlytumbled about with the result that no one point thereof remains incontact with the cathode bars.V Uniformity in plating is thusautomatically., insured.

As most clearly appears in Figure 1,`

when the nuts or other articles to be plated approach the end of aparticular treating bath, the propelling members operate to advance thearticles upwardly along the curved portion of the trough for subsequentdischarge into the receiving end of the next adjoining tank. In thismanner, the articles are progressively advanced through the continuousline of tanks Without necessitating any manual handling throughout theentire process of plating.

It will be understood, of course, that various changes may be. made fromtime to gitudinally along the bottom of said tank,.

thi*J opposite ends of said trough being curved upwardlytoward the upperedges of the tank and the bottom of said trough between the curvedportions thereof being corrugated, and means therealong operativelyassociated with said tank for continuously propelling a succession ofarticles to be vplated along the corrugated bottom and curved portionsof said trough,- said corrugated bottom being operative to eii'ect acons'tant shifting of the articles during their passage therealong.

2. In an electroplating apparatus, in combination, a tank adapted tocontain an electroplating solution, a corrugated work guiding pathextending longitudinally through said tank, and an endless conveyormechanism operatively arranged above said tank, said mechanism includinga plurality of work propelling members arranged in transverse relationto said corrugated path and adapted to move longitudinally through saidtank with the free ends thereof in close proximity to said path.

f 3. In an electroplating apparatus, in combination, a tank adapted tocontain an electroplating solution, said tank being provided in itsbottom with a` longitudinally extending path having corrugated surfacealong which the work may be propelled, an endless conveyor mechanismoperatively arranged above the tank, said mechanism including aplurality of work propelling members arranged in transverse relation tosaid longitudinally extending path for movement through said` tank withthe free ends thereof in'close proximity to the corrugated surfacethereof, 'means for supplying current to said solution, and'meansforiinsulating said members against excessive deposition of metalthereon.

4. An lapparatus for electrolytically coating small articles such as capnuts comprising a tank containing an electrolyte, a conveyor having aplurality of depending arms extending into said tank into proximity withthe bottom thereof and adapted to push successive articles through theelectrolyte contained in the tank, the bottom of said tank beingcorrugated. whereby to effect a tumbling of said articles during theirprogress through the tank.

In testimony whereof 'I hereunto aflix my signature.

JAMES lV. HUGHES.

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